class_docstr: Callable object storing the details of one alias.
  
  Instances are registered as magic functions to allow use of aliases.
code: def __repr__(self):
      return "<alias {} for {!r}>".format(self.name, self.cmd)
  
imports: import os
  import re
  import sys
  from traitlets.config.configurable import Configurable
  from .error import UsageError
  from traitlets import List, Instance
  from logging import error
label_desc: Use image node_id 3 for calling the Alias obj's underlying member method code with example usage: obj.__repr__() and returns: str